When combined, blue and orange produce a version of the colour brown. Brown is a tertiary colour because it is created by mixing main and secondary hues.
The basic colours are red, yellow, and blue, while orange, purple, and green are secondary colours. On the colour wheel, each primary colour is paired with a secondary colour. Orange and blue are complimentary hues, which means that they are directly opposite one another on the colour wheel. In addition, the complement of purple is yellow, and the complement of red is green. Combining any two complementary hues results in several shades of brown.